LAUSR

Persistent cognitive, affective, and motor symptoms have been associated with sports-related concussions including several neurophysiological changes in the primary motor cortex. In particular, previous research has provided some evidence of altered latencies of the corticomotor pathway and altered motor neuroplasticity. However, to date no studies have assessed these neurophysiological metrics in a common group of athletes across different phases of injury and recovery. Here corticomotor latencies and neuroplasticity were assessed in collegiate athletes with or without a history of prior concussion across two different phases of injury: either in an acute-state of concussion (within two weeks of injury) or in a chronic-state of concussion (more than 1 year after injury). Corticomotor latencies were determined by measuring the motor evoked potential (MEP) onset time and motor neuroplasticity was assessed by measuring MEP amplitudes following application of anodal transcranial direct current stimulation (tDCS) over the primary motor cortex (M1). We found that concussed athletes had slower corticomotor latencies than non-concussed athletes, and corticomotor latency was also positively correlated with the number of prior concussions. In contrast, there was no evidence of altered motor neuroplasticity in athletes regardless of concussion history. These findings suggest concussions may lead to permanent changes in the corticospinal tract that are exacerbated by repeated injury.